Heterogeneous Visual Acuity Chart Detecting Feigned Results
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Solution Overview
Problem
The existing visual acuity testing methods, particularly using the GB 11533 Standard for Logarithmic Visual Acuity Charts, face challenges in determining the authenticity of test results due to subjective cooperation and have large errors in low visual acuity tests, making it difficult to distinguish between true and feigned visual acuities.
Innovation Solution
A heterogeneous visual acuity chart is introduced, comprising optotypes of different sizes and a perspective that causes visual depth illusions, allowing for the differentiation between true and feigned visual acuities by altering the test distance and structure, including a size illusion chart with a heterogeneous reference zone and multiple optotype patterns to confuse the subject's size perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional visual acuity chart with fixed optotype directions and order is used, then the testing process is simple and quick, but the subject can memorize the chart structure to feign high visual acuity, reducing the reliability of test results
Solution Approach 1:
The patent implements dynamic randomization of optotype parameters including direction, size, and presentation order. The testing system randomly generates chart configurations for each test session, preventing subjects from memorizing fixed patterns. This dynamic approach maintains testing efficiency while ensuring result authenticity by making each test unique and unpredictable.
Solution Approach 2:
The patent performs preliminary randomization of optotype arrangements and parameters before the actual testing begins. By pre-generating random chart configurations and shuffling optotype sequences in advance, the system eliminates the possibility of subjects anticipating or memorizing test patterns, thereby preventing feigned high visual acuity while maintaining smooth test flow.
2Loss of time
If the number of optotypes in each row is reduced to 2-4 as per GB 11533 Standard, then the testing time is shortened, but the measurement precision of low visual acuity deteriorates with large errors
Solution Approach 1:
The patent dynamically adjusts the number of optotypes presented based on the subject's performance level and visual acuity being tested. For low visual acuity tests, the system increases the number of optotypes beyond the standard 2-4 to improve measurement precision, while for higher visual acuities it reduces the number to maintain quick testing. This adaptive parameter adjustment optimizes both testing efficiency and measurement accuracy across different visual acuity ranges.
Data Source
AI summary
A heterogeneous visual acuity chart and a visual acuity testing method and device are provided. The heterogeneous visual acuity chart is a size illusion chart composed of a heterogeneous reference zone and at least two types of optotypes of different sizes, where the heterogeneous reference zone is used to cause incorrect identification on the different types of optotypes of different sizes. The visual acuity testing method and device determine whether a visual acuity of a subject is true based on a difference between visual acuities tested with the heterogeneous visual acuity chart and a standard logarithmic visual acuity chart. The visual acuity chart is a size illusion chart composed of optotypes of different sizes and a perspective, which causes an illusion on a visual depth to interfere with the identification of the optotypes of different sizes.